Reaching ground level

I realized I had low self-esteem this year. And it's falling deeper fast. Now any word that makes me doubt myself even a little can throw me into a pool of emotional turmoil. Low self-esteem affects millions of people worldwide, and that may make it sound like something so ordinary it's not really your concern, but it's seriously no fun when you're the one with it.
I don't know how to deal with it. I have read articles and tips, but they barely are of any help. Or maybe I just don't put in enough effort. So what do I do to keep living till now?
Simple. Ignore the problem/run away from it. My drug, aka internet, makes it more bearable.
But even so, I can't help zoning out at certain points in my life to mull over the purpose of my existence. And it always comes down to the same answer: "Well, you don't have one. So die already and make space for other people who really matter in this world."
I see myself as:
"A worthless, useless, powerless, incompetent, ugly, pathetic piece of breathing junk littered on a microscopic spot in the world that the cleaners have missed. My existence is pointless as I leave no real impact on the world, be it good or bad. I am an utter disappointment and failure to myself and everyone who has even a blip of expectation in me. I am so weak I can lose to rice paper. I'm such a dimwit I'm dimmer than a failing bulb. I am a leech with no reason for you to give me attention or care, unless you've got that much time and effort to waste. I have no good reason for you not to kill me. I am a waste of space, time, resources and just about any other aspect that's needed and important for the continuation of life. All I can do is complain and bemoan my existence, as I wallow in my pool of self-criticism, disgust and hate. I shouldn't have existed. My place should have been given to someone else better."
In my eyes, everyone else is so much more than me, more worthy than me, more important than me. When it comes to opinions, I feel like I'm always wrong and others are right. I have no confidence in my opinions at all. Even if its something as sure as 1+1=2, if you doubt that, I'll start to doubt myself in turn. The fact that I'm easily misunderstood just adds to the problem; I began to think that maybe I'm not misunderstood, I'm just wrong.
Each situation where I am made to feel stupid, embarrassed or lesser in any way pushes me into a dark place. And that description above, I will repeat it over and over in my head.
Typing this out, I feel a little silly. Maybe I don't have the right to feel this way. And when I say that, another voice tells me that I indeed do not deserve to feel this way and something like, "get your lazy ass off the chair and prove it to the world you're someone who can be awesome and not to be messed with."
But that momentary resolve is very, very fragile. It will soon be overwritten by the huge ominous wave of self-criticism/can't-do-its and I'll be back where I started. I once thought that this mentality will just blow over, but it's only getting worse. I want to stop it, but I may have reached the end of my wits.